Top of Z axis (for Max)
Thank you, Daniel! Depends all of the whole weight only on two Motors?
Yes, it’s quite heavy that’s correct. The bed plate is 350x350mm, 6mm thick plus L profiles on the side, 3pcs of 20x20 profiles to connect both sides and a silicone heater. I guess around 1.5 kg.
Z acceleration is set to 300mm/s^2 and speed to 3mm/s. Thread is 2mm/revolution.
As the platform moves downwards during a print, it’s not so likely to loose steps while printing, but homing is hard work for the steppers. Steppers are 1.7A in parallel on a ramps with a a4988 driver. Threaded rods are oiled.
3 motors and adapted firmware would be nice–then you could to “real” auto bed leveling instead of adapting Z to a misaligned bed. But then more drivers would be needed, one per stepper motor.
My Z-axis have a support on bottom an 1:3 ratio with timing belts.
timing belts to drive a lead screw or to lift the bed?
@Daniel_F to drive a lead screw, Daniel. See my photos on profile.
But possible z go out of axis because is locked by only one bolt?
Maybe this is an interesting part for the bottom.
Yes, needs to be tightened hard, but i’s also easy to adjust. When tightened, it does not move. I thought about tapping the motor plate with m3 (but not the profile) and fix the plate against the profile with a scew.
I think what is not so good in my design is that the whole weight of the build platforms hangs on the steppers with their tiny bearings that are not made for axial load. This could result to early wearing out these bearings. Thanks @Erich_HaHaOh for the link with the axial bearings
@Daniel_F I have angular bearings on bottom of threaded rods. The are good for axial and radial loads the same time.
agree @Shauki, but as the weight is constant (if the weight of the printed object is disregarded), the stretching also stays constant, so I think it does not have a big impact. What problems could load on couplings lead to?
I could add a small socket (Hülse) with a grub screw (Madenschraube) just above my new bottom bearing. The question is whether the ABS parts support the weight over time, as they were not designed to hold the bed weight.
My build platform is heavy, maybe 1.5kg but it seems to work
@Daniel_F No, this plastic part on bottom must be based/supported, otherwise he will sag. And we need a precision. Take, please, angular contact ball bearings or aligning ball bearings.